I had an anal fissure last year around this time. It caused pain in the tailbone. I Started getting spasms in my anus which made it hard to even walk. I had to get surgery for my Fissure. They are not fun! The surgery worked like a charm and I have had zero problems since then.
Anal fissures normally will heal on their own, but there's always an exception to this. See a gastro doc to verify that you have a fissure and to answer any and all questions on the tail bone pain. Best wishes.